Coins are the main currency in the game. They can be used to buy Animals,Fun Stuff, Decorations, and Land Expansions.
Daily bonuses are almost always coins, with the fifth day being something special!
See the Earning Coins page for all the ways to get free coins while playing. The most common way to earn coins is to buy Animals, complete their families, and purchase Fun Stuff buildings such as Punching Bag, Mini-Golf, etc.
You can also purchase coins with real-world money.
Large amount of coins from the Piranha famiy.